It is my first grow, basically a friend with many years experience is helping me with it. He thinks that the negative pressure is enough that I wont need a filter. I am basically doing my own research as I don't want to get caught lol.
The chimney is high up as I am in a block of flats.
I'm actually in the UK. What other oder control is there? I have installed rubber seals round the doors of the room with the tent and also the front door. I also have thick black out fabric round the window which has masking tape sealing it.